A voice rose above the chatter in the University of Maryland parking lot: "Blind man driving!"

Twenty people took turns piloting a car on this muggy Friday morning, the first public test of technology that might one day overcome barriers to putting the blind behind the wheel.

The quest to drive has captivated the blind community as it has become more integrated into a car-centric society. Some likened Friday's test to a moon landing -- a fitting analogy, considering that the prototype vehicle vaguely resembled a lunar rover.

"One day, we'll be on the road with them," said Ishaan Rastogi, 15, a blind New Jersey high school student with a Yankees cap pulled over his eyes and the first to test the vehicle.

Virginia Tech engineers started work on the vehicle in response to a 2004 challenge from the blindness advocacy group to build a vehicle that the blind could drive with the same freedom as the sighted.

"Blind people can do all sorts of things that the public doesn't think we can do," said Chris Danielsen, spokesman for the federation. The blind can read ordinary books with a hand-held device that translates type to synthetic speech. Adaptive devices permit blind users to interact with computers and surf the Internet.

Driving without sight became a conceivable goal in this decade with the development of autonomous, computer-guided vehicles. The Defense Advanced Research Projects Agency ran a series of contests to inspire a driverless car that could navigate complex terrain. By 2007, vehicles from Virginia Tech and several other universities could complete the DARPA course.

The design team first sought to customize Virginia Tech's entry in the 2007 DARPA contest, a modified Ford Escape that finished third in the competition. But the engineers decided it would be easier to start from scratch. They purchased an all-terrain vehicle online for $1,300 in fall 2008 and began anew.

They mounted a laser sensor to the front of the vehicle to sweep the terrain ahead and return a signal. A powerful computer at the rear of the buggy interprets the signal to build a two-dimensional map, showing obstacles in the vehicle's path.

But how to show that map to a person who cannot see?

Researchers boiled down the data to two crucial factors: direction and speed. A computer voice signals the driver through headphones how to steer to avoid a collision -- one click to the left, for example; three clicks to the right.

"We call it a back-seat driver," Lippy said.

The increments correspond to notches cut from the steering wheel. The driver turns the wheel and hears an audible "click."

The computer communicates speed with vibrations fed through a vest worn by the driver. Stronger vibrations indicate it is time to stop. Sensors automatically kill the engine if the vehicle gets too close to an impediment. For the test drives, engineers rigged the buggy for a top speed of 15 mph.

One by one Friday morning, drivers buzzed around Parking Lot 1D, empty save for traffic cones placed at intervals around light poles. There were no mishaps.

"It's finally a chance to drive," said Angel Reyes, 16, a junior at New Brunswick High School in New Jersey, as he climbed from the vehicle. "Finally a chance to be more independent in getting where you want to go."

When the team first tested the buggy in May, three blind drivers completed a curved course without hitting a single cone. In fact, the blind drivers -- who had never driven before -- fared better than the engineers themselves, who tried steering the car blindfolded. Lippy thinks that the experienced drivers tended to ignore the computer signals and follow their own instincts; the blind drivers obeyed the computer to the letter.

The blind drivers posed questions that had not occurred to the engineers. How would they find the vehicle in a parking lot? If they had to jump the battery, how could they tell the positive cable from the negative?

The engineers say their first Blind Driver Challenge vehicle is crude. The computer can sense and avoid obstacles but cannot plot a course to a destination. The team is working on a more sophisticated interface to deliver signals to drivers. Their goal is to convert the two-dimensional map plotted by the computer into something a blind driver can touch.

They have tested a grid of air holes that shoot bursts of air, using various pulses and pressures, to convey topographical data. (A higher pressure could signal hills or bumps.)

"You have to understand, this is a prototype," said Dennis Hong, an associate professor at Virginia Tech who directs the robotics lab. "First time in the history of mankind."

He predicts a safe, stable technology for blind motorists will arrive "within the next three years. The problem is not the technology. The problem is public perception and legal issues."

He urges detractors to think of the last time they flew in an airplane. "On autopilot," he said. "Nobody questions that."